1. Field of the Invention
The present invention relates to an ophthalmic apparatus, and more particularly to an ophthalmic apparatus usable as apparatus of battery type and of hand-held type.
2. Description of Related Art
In general, the on-off control of electric power to cornea shape measuring apparatuses, fundus cameras and the like is performed by examiners using a manual switch. In the case where an examiner operates the apparatus with switches, however, if the examiner forgets to turn off the power supply after use, the life of electrical parts such as a lamp and the like is shortened and electric power is unnecessarily consumed. To overcome the above problems, some conventional apparatuses are provided with an auto-off function for automatically turning off the power supply if no operation is carried out for a prescribed time.
However, in the conventional apparatus loaded with the auto-off function, the power supplied to a microcomputer circuit etc. is not turned off even when operation is not performed, so that the unnecessary consumption of electric power can not be prevented sufficiently. The resulting drawback is the need for frequent battery charges or replacement of the battery apparatus of battery driving type.
To store sufficient electric power by one charge or change of battery in the battery type apparatus, the battery capacity thereof is required to be enlarged. As a result, the cost will increase and also the battery will be enlarged in size. This may be disadvantageous for apparatuses of hand-held type in particular.
The apparatus provided with the auto-off function has further a problem that return to an active condition from an auto-off condition needs a switching operation, and therefore, it is a cause of trouble.